This invention relates to a method of preventing unauthorized use, particularly a method of preventing unauthorized use of data or software such as programs stored on a recording medium such as an optical disk, a floppy disk or a magnetic disk.
The spread of large-capacity, portable recording media such as optical disks, floppy disks and magnetic disks has been accompanied by an increase applications that deal with large quantities of digital information. As a result, there has been a great increase in such digital information as data in image files and word-processor documents, games, word processing software and application programs for CAD or the like.
Information recorded on a recording medium such as an optical disk is digital information and is characterized by the fact that it can be recorded on other media without experiencing any decline in quality. Put another way, this feature of digital information means that it can be copied with ease. A problem that arises here is that confidential information as well as data and software such as application programs not purchased legally can be used upon being copied unlawfully from the original (the original recording medium). The losses sustained by software developers is immeasurable. Such unlawful copying is a violation of copyright laws and hinders the spread of such media as large-capacity, portable optical disks. Accordingly, an effective method of preventing unauthorized or unlawful copying is required.